1. Field of the Invention
The invention relates to a plate-link chain for a continuously variable transmission of a motor vehicle.
2. Description of the Related Art
A plate-link chain is in the sense of the present invention a wrap-around member that has several chain links that in each case extend in the wrap-around, that is, in a running, direction, of which each of two adjacent link elements are linked together in an articulated manner.
The chain links in each case have several elements, which in the sense of the present invention are shown as plates, and that are particularly formed small-plate-like, so that their thickness is comparatively small in comparison with their length and in comparison with their width. The links, that are especially in the form of stampings, include through-openings.
In the sense of the present invention a link element is in particular a device with two rocker members that are arranged to be movable against each other. Those two similar link elements have adjoining rocker members that have in each case a surface, a so-called rocker surface, that is associated in each case with a corresponding rocker member of the link element and that can roll on the rocker surface of the associated rocker member. In particular, the rocker members are associated with different adjacent chain links. Especially, each of the rocker members is non-rotatably connected with its associated chain link, namely in relation to the longitudinal axis of the link element. This non-rotational connection in particular is positively formed. The plate-link chain is particularly constructed in the manner so that at least one rocker member of a link element is movable in the longitudinal direction of the rocker member relative to the plate-link chain, and/or at least one part of the plate link, through which the rocker member extends, is movable relative to the rocker member in the direction of the longitudinal axis of the rocker member.
In particular a plate-link chain in the sense of the present invention is constructed in such a way that for each link element at least one rocker member projects laterally from the plate-link chain. The rocker members associated with a link element can have the same or a different construction. Those equal rocker members associated with the link element have, in particular, a different length. Preferably at least one rocker member of a link element has a sloping and/or a rounded end face.
A continuously variable transmission is in the sense of the present invention in particular a transmission apparatus that, in a predetermined transmission ratio range, can be operated steplessly at different, that is, all, transmission ratios between an input and an output shaft. This transmission has in particular two pairs of conical disks, of which one pair is connected to the input shaft and one pair is connected with the output shaft. The conical disks of the pairs of conical disks are in each case arranged to be axially movable relative to each other and can receive a plate-link chain in the gap area between them, whereby in the sense of the present invention it is especially provided that one of such plate-link chains is positively connected with the respective conical-disk pairs over different end faces of several rocker members of a link element of the plate-link chain, so that a torque can be transmitted between those conical disks by way of the plate link chain.
The continuously variable transmission has in particular an actuation apparatus, which preferably is of hydraulic form, and can control changes in the spacing of the respective conical disk pairs, and, to be sure, especially simultaneously, so that with the enlargement of the distance between the conical disks of a first conical disk pair a reduction of the distance between the conical disks of the second conical disk pair proceeds, and the plate-link can also transmit a torque between the conical disk pairs during an adjustment of the transmission ratio of the transmission.
A plate-link chain with a retaining element is already known from the German DE 198 55 582. That known plate-link chain has several chain links with plate links that are connected over link elements with rocker member pairs, whereby the rocker members are non-rotationally secured in the plate links and whereby one of the retaining links provided as outer links permits a change in spacing of the rocker members and prevents an outward migration.
The object of the present invention is to create a plate-link chain, by which by structurally simple and economical methods with higher strength of the link elements, that prevents the plate links and/or the rocker members from laterally migrating out of the plate-link chain, and which provides higher strength.
The object is solved through a plate-link chain as hereinafter described.
Preferred improvements of the invention are also disclosed hereinafter.
In accordance with the invention a plate-link chain is proposed that has at least one rocker member, in which a recess extends, that particularly is ground in the respective rocker member. In that recess of the rocker member at least one retaining element is engaged, and to be sure in such a way, that through the retaining element, if necessary in cooperation with other elements, particularly further retaining elements, the movability of the rocker element against at least one plate link of the plate-link chain in the direction of the longitudinal axis of the rocker member and the link element, respectively, that this rocker member has, at least restricts, especially prevents. Preferably this retaining element has a bow-shaped form.
The invention is advantageous to the extent that it secures the rocker members in a dependable way and method, the retaining elements can be releasably attached against the rocker members, and because of the retaining elements the rocker members undergo substantially no appreciable loss of strength. Particularly in a straight segment of the plate-link chain, the rocker members are positively secured against falling out.
Preferably the retaining element has a bow-shaped form.
In accordance with the invention, a plate-link chain is proposed that has at least one retaining element which at least limits and particularly prevents the movement of a rocker member relative to at least one plate link in the direction of the longitudinal axis of the rocker member, that is, the longitudinal axis of the link element. In that case a rocker member has at least one recess. The at least one retaining element has at least one free end, and especially two free ends, so that at least one rocker member is connected with the retaining element in a form-locking and/or friction-locking manner, without the rocker member being received in a peripheral direction in a closed opening of the retaining element. It is preferred that at least one rocker member is received in a peripherally closed opening of the retaining element and is connected with the retaining element in a frictionally-locked and/or a form-locked manner, whereby the retaining element further has a free end that is form and /or frictionally connected with at least one additional rocker member.
The retaining element limits and/or prevents rocker member movement relative to at least one plate link in the longitudinal direction of the rocker member as well as the link element.
The retaining element preferably has two open ends. Especially preferred is that the retaining elements is releasably engaged in the recess. The retaining element, which preferably is elastic in the direction of chain movement, preferably grips at least two recesses of different rocker members.
Especially preferred, the retaining element presses against a recess when in assembled condition. That is particularly realized in that the retaining element itself applies a clamping force, whereby the retaining element in particular is biased and the clamping force is generated by the resulting biasing force.
In accordance with a preferred embodiment of the invention, a retaining element extends into a recess, and, to be sure, without loading the bottom area of the recess with a clamping force.
Preferably at least one groove-shaped or hole-shaped recess is formed and has a constant or a varying depth.
Preferably the recess extends at least partially straight and/or at least partially curved.
Especially preferred, a recess extends substantially parallel with the longitudinal axis of a link element, or at an angle different from 0xc2x0 to that longitudinal axis. Preferably at least one recess extends at least partially around a link element, that is, around a central longitudinal axis of a rocker member. Especially preferred, the groove thereby runs on a circle or along an arc of circle or along a helical path.
Especially preferred, a recess extends along a longitudinal axis of the link element and a rocker member, respectively, and thereby encompasses in a peripheral direction an angle of at least 45xc2x0, especially preferred at least 90xc2x0, especially preferred at least 180xc2x0, especially preferred at least 270xc2x0, which preferably is less than 360xc2x0.
Preferably at least one rocker member has a recess in one or in both of its end areas.
Preferably at least one rocker member is formed without a recess.
Preferably at least one recess extends along the peripheral surface and/or on at least one front face of a rocker member.
Especially preferred, at least one retaining element contacts a rocker member frictionally or force lockingly.
In accordance with an especially preferred embodiment of the invention, at least one retaining element extends substantially parallel to an adjacent plate link of the plate link arrangement and/or substantially in the direction of movement of the plate-link chain.
Preferably retaining elements are provided in each case in the end areas of the rocker members or the link elements, so that between the retaining elements of the chain link in question a chain link extends that is associated with a plate link arrangement.
In accordance with an especially preferred embodiment of the invention, there is in at least one link element a chain link of this link element, that is, at least one rocker member of that link element that is in an area that lies outside of the link arrangement through a retaining element that is form-lockingly secured, and a second outer area lying on the other side of the chain, through a retaining element that is secured force- or frictionally locked.
The frictionally locked retaining element engages particularly at least two rocker members or at least two link elements.
Especially preferred, a retaining element engages in each case in at least one recess and runs from at least two rocker members or at least two link elements.
Preferably, one retaining element engages each recess of four rocker members.
In accordance with an especially preferred embodiment of the invention, at least one rocker member is force-lockingly secured and at least one rocker member is form-lockingly secured by means of one retaining element.
In accordance with a preferred embodiment of the present invention, at least one retaining element contacts at least one rocker member and/or at least one link element on two different sides, so that the rocker member or the link element is clamped by the retaining element. Particularly, the retaining element contacts the rocker member or the link element on two substantially oppositely-lying surface areas on the outer periphery. Especially preferred, the retaining element contacts different rocker members on their peripheral areas and thereby clamps the rocker members. In accordance with an especially preferred embodiment of the invention, one retaining element contacts at least one rocker member in each case on oppositely-lying front faces.
In accordance with an especially preferred embodiment of the invention, at least one retaining element has two free ends, whereby the retaining element in the area of its free ends clamps at least one rocker member or at least one link element.
Preferably, the clamped rocker members and/or the clamped pairs of rocker members are clamped by means of oppositely-directed loads by the retaining elements, whereby the load is particularly a pressure load or a tension load.
The retaining element prevents or restricts in particular any movement between at least one plate link and at least one link element or at least one rocker member, and to be sure in either or in both directions.
In accordance with a preferred embodiment of the invention, at least one recess extends in one rocker surface of at least one rocker member.
In accordance with an especially preferred embodiment of the invention, the rocker members of a pair of rocker members each have at least one recess, in which the same retaining element is engaged, whereby the recesses extend particularly on the outer peripheral surfaces of the rocker members or on the rocker surfaces.
Preferably at least one retaining element extends from a first link element to an adjacent link element and in each case engages a recess.
Especially preferred, the four rocker members of two adjacent link elements each have at least one recess in which the same retaining element engages.
In accordance with a preferred embodiment of the invention at least one retaining element engages a recess that is arranged on a front face of a rocker member.
Preferably at least one rocker member has a recess on its outer surface or peripheral surface, which especially preferably extends on the rocker member surface that faces away and in which a retaining element is gripped.
In accordance with an especially preferred embodiment of the invention the plate-link chain has at least two differently-constructed or formed retaining elements.
In accordance with an especially preferred embodiment of the invention, a retaining member has at least two free ends, whereby the retaining element grips the rocker members in such a way that the free ends are directed to the outside or to the inside of the chain.
The inner side of the chain in particular is the side that faces the axes of the conical disks.
In accordance with an especially preferred embodiment of the invention different retaining elements are provided in one plate-link chain, which are formed identically or differently, and which relative to the respective link elements that are engaged by the retaining elements, are arranged differently. Particularly, one retaining element engages in such a way that the free ends are directed to the outside, while a second retaining element engages in such a way that the free ends are directed to the inside of the plate-link chain.
In accordance with an especially preferred embodiment of the invention, at least one retaining element of the plate-link chain has two free ends, of which at least one is formed as a bend.
In accordance with an especially preferred embodiment of the invention two relatively immovable and/or non-rotatable rocker members are connected by means of some retaining elements, and particularly by means of some wire bows. The retaining element or retaining link or the wire bow is particularly arranged in accordance with the invention so that the retaining element or wire bow is during operation exposed to no or only very small dynamic stresses.
Further preferred, the retaining element, which is particularly formed as a wire bow, shows only a small bending stress at wear risk areas.
In accordance with the invention it is proposed to form a plate-link chain in such a way that at within at least one chain link at least two plate links are arranged, which are at an included angle with each other so that they are not arranged in parallel.
Preferably, to each of the plate links within the same chain link that are at an included angle with each other there is arranged at least one additional parallel plate link.
Preferably, the plate links within one chain link are arranged in the form of a V, whereby the V-form is open or closed in the direction of movement of the plate-link chain.
It should be pointed out that the cooperation between individual features of the invention is preferred in any arbitrary combination. In particular, combinations of features disclosed by the independent claims also always are preferred when omitting one or more features.
It should further be noted that the discussions relating to all known apparatus not related to specific documents are known foremost to the applicant or to the inventor, and therefore the inventor reserves protection for those that are not known to the public.
It should be noted that when features are linked by xe2x80x9cor,xe2x80x9d the xe2x80x9corxe2x80x9d always means on one hand a mathematical xe2x80x9corxe2x80x9d and on the other hand always the xe2x80x9corxe2x80x9d that excludes the other possibility.
It should further be noted that the concept of control as well as its derived concepts are to be construed widely in the sense of the invention. In particular it includes regulation and/or control in the sense defined in DIN.
It is clear to the expert that a plurality of further modifications and embodiments of the invention are conceivable beyond the exemplary embodiments disclosed herein and are covered by the invention. In particular the invention is not restricted to the embodiments discussed herein.
The invention further concerns a plate-link chain in particular for a steplessly variable gear ratio, conical-disk transmissions, such as CVT transmissions, of which the individual chain links are formed from sets of plate links connected by articulation members, preferably as pairs of rocker members having rocker faces braced against each other and that are inserted into recesses in the plate links. The invention also concerns a method for manufacturing such a chain.
Such plate-link chains are known in the state of the art. Examples are DE 197 08 865 and the documents cited therein, EP 0 518 478 and EP 0 741 255.
In plate-link chains of those kinds, to increase the load carrying capacity after assembly of the plate links and rocker members in a straight strand and an open formation, a stretching process is carried out by applying substantial tension forces to the extended plate-link chain. In that way the contact areas of the plate links between the plate links and the rocker members of all plate links of a row are equally plastically deformed. By stretching in a straight strand there arises an equalized plastic deformation of the plate links in the contact areas, so that the plate links of one row of plate links are equally elongated over the width of the plate link or exhibit equal lengths. That has the disadvantage that when the plate-link chain is under load during operation of a stepless, variable transmission the chains do not exhibit optimal service life and performance capacity.
An object of the invention is to create a plate-link chain and a method for its manufacture which, relative to the plate-link chains of the state of the art particularly, withstand higher operating loads or, at equal loads, have a longer service life.
In accordance with the invention the object is achieved for the above-designated plate-link chains in that the plate-link chain is stretched when in a closed condition.
The object of the invention is also solved in that for a plate-link chain of the type described above the plate links have a different plate link inner width as a function of the chain width. That can be achieved in accordance with the invention by stretching the plate-link chain in the closed condition as a wrap-around member.
The concept of plate link inner width corresponds with the distance between the contours on which both outer rocker members lie against the plate link. That is thus a distance that is not dependent upon whether the plate link has a central opening or two openings to receive the rocker members. Furthermore, it is presented in the figure descriptions.
It is advantageous from another embodiment, however, to manufacture the plate links by different manufacturing processes, such as a stamping process or a cutting process, for example by means of a laser, or the like, and the individual plates are stretched equally or differently and are assembled together, or the assembled chain is stretched in the wrap-around condition.
It is also appropriate by a further embodiment to produce the plate links by a stamping process with equal plate link inner widths, and that are differently stretched and assembled together. The stretching can in this embodiment also be carried out on the individual plate links before assembly or in the wrap-around condition on an assembled chain.
According to a further inventive concept, the object of the invention can also be achieved by an above-designated plate-link chain in which the plate links exhibit a different degree of stretch as a function of the chain width.
That result can thereby be advantageously achieved by stretching to a different degree of stretch the plate links having the same or different plate link inner widths and assembling them together. That can also be achieved by stretching in the wrap-around condition.
According to a further inventive concept, the object of the invention can also be solved for an above-designated plate-link chain in which the plate links, as a function of the chain width, exhibit a different angle considered between the contact areas and an axis that is oblique to the chain longitudinal direction. Thereby a modulation or variation of the angle over the chain width is achieved, which permits a relatively good fit or installation of the plate links on which in operation of the chain the rocker members are partly bent
According to a further inventive concept the object of the invention for an above-designated plate-link chain can also be solved in that the stretching load that impacts on the plate links by a stretching process has a variable angle in relation to the plate-link length direction. Thereby the plate links are stretched at different places in their contact areas and therewith strengthened in that manner, so that they exhibit sufficient strength when loaded during the operation of the chain, both in a straight strand between the conical disk pairs and in the area of the conical disk pairs.
It is particularly advantageous when the plates are individually stretched and subsequently assembled to each other. By another embodiment it is appropriate for the plate links to be stretched when in assembled condition of the closed chain, such as particularly in the wrap-around mode when arranged between two sets of conical disks of an apparatus.
The invention advantageously applies to plate-link chains in which at least one of the respective end faces of the rocker members per link associated with a conical disk carries the frictional forces between the conical disks and the plate-link chain. It can therefore be appropriate according to each application instance of the exemplary embodiments for the rocker elements to have the same length or different lengths.
The invention advantageously also applies to plate-link chains in which the plate-link chain has, in addition to rocker members, connecting pins that carry the frictional forces between conical disks and the plate-link chain.
It is particularly advantageous when the plate links adjacent to the edge of the plate-link chain are more highly elongated than those plate links arranged in the middle of the plate-link chain, or when the plate links adjacent to the edge of the plate-link chain have a larger plate link inner width than those plate links arranged in the middle of the plate-link chain.
Furthermore, it is appropriate when as a result of a stretching process contact areas of the plate links with the rocker members are in that manner plastically deformed, that an angle is formed between the contact areas and a direction oblique to the longitudinal direction of the chain.
A plate-link chain in accordance with the present invention includes a chain in which the plastic deformation of the contact areas of the plate links adjacent to the edge of the plate-link chain is greater than that for the plate links arranged at the middle of the plate-link chain. It is also appropriate for the plastic deformation of the contact areas of the plate links over the width of the chain to take on a curved-shape contact area or a shape of an nth degree polynomial.
Especially advantageously, the plate-link chain is stretched in a stretching process with the chain included in the conical disk gap between two pairs of conical disks, and rotation and/or torque is applied.
It is also suitable for the strain in the plate-link chain to result from a stretching process under an axial load by pressing together the conical disks and/or by pulling apart from each other the axes of the pairs of conical disks. Correspondingly, the invention also applies to apparatus for stretching a plate-link chain. Thereby, it is appropriate that the conical disks of a pair of conical disks are displaceable relative to each other or are fixed.
When stretching the plate-link chain it is appropriate for the applied torque applied during the stretching process to be substantially higher than the nominal torque that is provided during the operation of a transmission provided with a plate-link chain.
It is also appropriate for the applied torque during the stretching process to be in the range of between zero and ten times, especially three times to five times, the nominal torque during the operation of a transmission provided with a plate-link chain.
It is also appropriate for the tension in the strand of the chain during the stretching process to be higher than the nominal tension during operation of a transmission provided with a plate-link chain.
The invention also refers to a process for manufacturing a plate-link chain particularly as claimed in one of the foregoing claims. The invention also refers to a process for stretching a plate-link chain.